.header {
	position: fixed;
	top: 0;
	left: 0;
	right: 0;
	z-index: 3;
	height: 60px;
	line-height: 60px;
	padding: 0 10px;
	font-size:20px;
	color: #fff; 
}
.header__logo {
	position: absolute;
	position: absolute; /* 垂直居中 */
	top: 50%;
	margin-top: -20px; /* 垂直居中，高度一半的负数 */
	height: 40px;
	line-height: 40px;
	text-indent: 45px;
	background: url('../images/logo.png') left center no-repeat;
	background-size: 40px 40px;
	text-indent: 50px;
	cursor: pointer;
}
.header__menu {
	position: absolute;
	right: 35px;
	height: 40px;
	line-height: 40px; 
	top: 50%;
	margin-top: -20px;
}
.header__menu-item {
	position: relative;
	display: inline-block;
	width: 75px;
	/* text-align: center; */
	height: 40px;
	line-height: 40px; 
	font-size:18px;
	margin-right: 35px;
	cursor: pointer;
}
.header__menu-item:last-child {
	margin-right: 0;
	border-bottom: 0;
	width: 100px;
}
.header__menu-btn {
	display: inline-block;
	height: 40px;
	line-height: 40px; 
	background-color: #f01400;
	color:#fff;
	width: 95px;
	border:none;
	border-radius: 5px;
	cursor:pointer;
	font-size:15px;
}
.header__menu-btn:hover {
	background: #cb1313;
}
/* .header__menu-item_active {
	border-bottom: 2px solid #f00;
} */
/* 滑动特效 */
.header__nav-tip{
	position: absolute;
	width: 75px; 
	height: 2px;
	background: #f00;
	left: 0;
	bottom: -5px;
	transition:  all .5s;
} 


/* 第一屏 */
.screen-1 {
	height: 640px;
	overflow: hidden;
	background: url('../images/sc1.jpg') no-repeat;
	background-size: cover;
	text-align: center;
	color: #fff;
} 
/* 垂直居中 */
.screen-1:before {
	content: '';
	display: inline-block;
	vertical-align: middle;
	height: 100%;
}
.screen-1__wrap {
   	display: inline-block;
   	vertical-align: middle;
   	width: 1200px;
   	margin: 0 auto;
}
/* 垂直居中 end */
.screen-1__head {
	font-size:35px;
	line-height: 35px;
	margin-bottom: 10px;
}
.screen-1__sub-head {
	font-size: 14px;
	line-height: 28px;
}


/* 第二屏 */
.screen-2 {
	position: relative;
	height: 640px;
	overflow: hidden;
	text-align: center;
}
.screen-2__wrap {
	width: 1200px;
   	margin: 0 auto;
}
.screen-2__head {
	margin-top: 90px;
	font-size: 35px;
	font-weight: bold;
	line-height: 35px;
	margin-bottom: 35px;
}
.screen-2__border {
	width: 50px;
	height: 4px;
	background-color: #f00;
	margin: 0 auto;
}
.screen-2__sub-head {
	font-size: 15px;
	line-height: 25px;
	margin-top: 20px;
}
.screen-2__bg {
	position: absolute;
	width: 750px;
	height: 361px;
	left: 50%;
	margin-left: -375px;
	bottom: 0;
	background: url('../images/sc2.png') no-repeat;
	background-size: contain;
}
.screen-2__bg-1 {
	position: absolute;
	width: 275px;
	height: 380px;
	bottom: 0;
	left: 50%;
	margin-left: -138px;
	background: url('../images/sc2-1.png') no-repeat;
	z-index: 2;
}
.screen-2__bg-2 {
	position: absolute;
	width: 266px;
	height: 205px;
	bottom: -100%;
	left: 48%;
	background: url('../images/sc2-2.png') no-repeat;
	z-index: 1;
}


/* 第三屏 */
.screen-3 {
	position: relative;
	height: 640px;
	background-color: #2b333b;
	color: #fff;
	overflow: hidden;
	
}
.screen-3__bg {
	position: absolute;
	width: 580px;
	height: 640px; 
	left: 140px;
	background: url('../images/sc3.png') no-repeat;
	background-size: cover;
}
.screen-3__wrap {
	float: right;
	margin-right: 200px;
	width: 700px;
}
.screen-3__head {
	width: 500px;
	margin-top: 220px;
	line-height: 35px;
	font-size: 35px;
	font-weight: bold;
	margin-bottom: 35px;
}
.screen-3__border {
	width: 50px;
	height: 4px;
	background: #f00;
}
.screen-3__sub-head {
	width: 500px;
	font-size: 15px;
	line-height: 25px;
	margin-top: 20px;
}
.screen-3__features {
	position: absolute;
	bottom: 50px;
	width: 600px;
	height: 70px;
}
.screen-3__features-item {
	display: inline-block;
	width: 70px;
	height: 70px;
	line-height: 70px;
	text-align: center;
	margin-right: 35px;
	border-radius: 50%;
	cursor: pointer;
}
.screen-3__features-item:last-child {
	margin-right: 0;
}
.screen-3__features-item1 {
	border:3px solid #1f5975;
	color:#108590;
}
.screen-3__features-item2 {
	border:3px solid #424d76;
	color:#6b658f;
}
.screen-3__features-item3 {
	border:3px solid #6b4146;
	color:#ff6060;
}
.screen-3__features-item4 {
	border:3px solid #29535f;
	color:#249d85;
}
.screen-3__features-item5 {
	border:3px solid #3e4e40;
	color:#66b056;
}

/* 第四屏 */
.screen-4 {
	height: 640px;
	overflow: hidden;
}
.screen-4__wrap {
	width: 1200px;
	margin: 0 auto;
	text-align: center;
}
.screen-4__head {
	margin-top: 90px;
	line-height: 35px;
	font-size: 35px;
	font-weight: bold;
	margin-bottom: 35px;
}
.screen-4__border {
	width: 50px;
	height: 4px;
	background: #f00;
	margin: 0 auto;
}
.screen-4__sub-head {
	font-size: 15px;
	line-height: 25px;
	margin-top: 20px;
}
.screen-4__environment {
	height: 150px;
}
.screen-4__environment-item {
	position: relative;
	margin-top: 75px;
	display: inline-block;
	margin-right: 120px;
	height: 150px;
	width: 180px;
}
.screen-4__environment-item-title {
	position: absolute;
	bottom: 30px;
	width: 180px;
}
.screen-4__environment-item:last-child {
	margin-right: 0;
}
.screen-4__environment-item1 {
	background: url('../images/sc4-1.png') center top no-repeat;
}
.screen-4__environment-item2 {
	background: url('../images/sc4-2.png') center top no-repeat;
}
.screen-4__environment-item3 {
	background: url('../images/sc4-3.png') center top no-repeat;
}
.screen-4__environment-item4 {
	background: url('../images/sc4-4.png') center top no-repeat;
}

/* 第五屏 */
.screen-5 {
	height: 640px;
	overflow: hidden;
	background: url('../images/sc5.jpg') no-repeat;
	background-size: cover;
	text-align: center;
	color: #fff;
}
.screen-5__bg {
	width: 1200px;
	height: 200px;
	background: url('../images/sc5-1.png') center no-repeat;
	margin: 100px auto 0;
}
.screen-5__head {
	margin-top: 40px;
	line-height: 35px;
	font-size: 35px;
	font-weight: bold;
	margin-bottom: 35px;
}
.screen-5__border {
	width: 50px;
	height: 4px;
	background: #fff;
	margin: 0 auto;
}
.screen-5__sub-head {
	font-size: 15px;
	line-height: 25px;
	margin-top: 20px;
}

/* 继续学习 */
.go-on-study {
	padding: 70px 0;
}
.go-on-study__btn {
	display: block;
	width: 200px;
	height: 60px;
	line-height: 60px;
	background-color: #fff;
	border:1px solid  #707070;
	margin: 0 auto;
	border-radius: 5px;
	cursor: pointer;
}
.go-on-study__btn:hover,
.footer__nav-item:hover {
	color:#f00; 
}

/* footer */
.footer {
	height: 110px;
	background-color: #000;
	color:#fff;
}
.footer__nav {
	width:800px;
	margin: 0 auto;
	padding-top: 30px;
}
.footer__nav-item {
	display: inline-block;
	margin: 0 20px;
	line-height: 30px;
	cursor: pointer;
}
.footer__copyright {
	margin-top: 10px;
	line-height: 30px;
	text-align: center;
	color:#666;
	cursor: pointer;
}

/* 右侧大纲 */
.outline {
	position: fixed;
	padding: 5px 10px;
    bottom: 120px;
    right: 0;
    background-color: #fff;
    box-shadow: 0 2px 12px 0 rgba(0, 0, 0, 0.1);
    z-index: 3;
}
.outline__item {
	width: 40px;
    height: 30px;
    line-height: 30px;
    padding: 5px 0;
    background: rgb(255,255,255);
    margin: 5px 0px 0px;
    border-top: 1px solid #eee;
    text-align: center;
    color: #93999f;
    cursor: pointer;
}
.outline__item:first-child {
	border-top: 0;
}
.outline__item_active {
	color:#f00;
}